﻿using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Windows;
using System.Windows.Controls;

namespace MIXer.Customization
{
    public static class PasswordHelper
    {
        #region Fields
        private static byte[] _key;
        private static byte[] _iv;
        private static TripleDESCryptoServiceProvider _provider;

        public static readonly DependencyProperty PasswordProperty = DependencyProperty.RegisterAttached("Password", typeof(string), typeof(PasswordHelper), new FrameworkPropertyMetadata(string.Empty, OnPasswordPropertyChanged));
        public static readonly DependencyProperty AttachProperty = DependencyProperty.RegisterAttached("Attach", typeof(bool), typeof(PasswordHelper), new PropertyMetadata(false, Attach));
        private static readonly DependencyProperty IsUpdatingProperty = DependencyProperty.RegisterAttached("IsUpdating", typeof(bool), typeof(PasswordHelper));
        #endregion

        #region Constructors
        static PasswordHelper() 
        {
            _key = System.Text.ASCIIEncoding.ASCII.GetBytes("GSYAHAGCBDUUADIADKOPAAAW");
            _iv = System.Text.ASCIIEncoding.ASCII.GetBytes("USAZBGAW");
            _provider = new TripleDESCryptoServiceProvider();
        }
        #endregion

        #region Methods
        public static string Encrypt(string plainText)
        {
            return Transform(plainText, _provider.CreateEncryptor(_key, _iv));
        }

        public static string Decrypt(string encryptedText)
        {
            return Transform(encryptedText, _provider.CreateDecryptor(_key, _iv));
        }

        private static string Transform(string text, ICryptoTransform transform)
        {
            if (text == null)
            {
                return null;
            }

            using (MemoryStream stream = new MemoryStream())
            {
                using (CryptoStream cryptoStream = new CryptoStream(stream, transform, CryptoStreamMode.Write))
                {
                    byte[] input = Encoding.Default.GetBytes(text);
                    cryptoStream.Write(input, 0, input.Length);
                    cryptoStream.FlushFinalBlock();

                    return Encoding.Default.GetString(stream.ToArray());
                }
            }
        }

        public static void SetAttach(DependencyObject dp, bool value)
        {
            dp.SetValue(AttachProperty, value);
        }

        public static bool GetAttach(DependencyObject dp)
        {
            return (bool)dp.GetValue(AttachProperty);
        }

        public static string GetPassword(DependencyObject dp)
        {
            return (string)dp.GetValue(PasswordProperty);
        }

        public static void SetPassword(DependencyObject dp, string value)
        {
            dp.SetValue(PasswordProperty, value);
        }

        private static bool GetIsUpdating(DependencyObject dp)
        {
            return (bool)dp.GetValue(IsUpdatingProperty);
        }

        private static void SetIsUpdating(DependencyObject dp, bool value)
        {
            dp.SetValue(IsUpdatingProperty, value);
        }

        private static void OnPasswordPropertyChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            PasswordBox passwordBox = sender as PasswordBox;
            passwordBox.PasswordChanged -= PasswordChanged;

            if (!(bool)GetIsUpdating(passwordBox))
            {
                passwordBox.Password = (string)e.NewValue;
            }
            passwordBox.PasswordChanged += PasswordChanged;
        }

        private static void Attach(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            PasswordBox passwordBox = sender as PasswordBox;

            if (passwordBox == null)
                return;

            if ((bool)e.OldValue)
            {
                passwordBox.PasswordChanged -= PasswordChanged;
            }

            if ((bool)e.NewValue)
            {
                passwordBox.PasswordChanged += PasswordChanged;
            }
        }

        private static void PasswordChanged(object sender, RoutedEventArgs e)
        {
            PasswordBox passwordBox = sender as PasswordBox;
            SetIsUpdating(passwordBox, true);
            SetPassword(passwordBox, passwordBox.Password);
            SetIsUpdating(passwordBox, false);
        }
        #endregion
    }
}